System for detecting display driver error when failing to receive a synchronization signal and method thereof

ABSTRACT

A system performs a method for detecting display driver error. The method includes sending a first command signal to a display driver to operate according to a first operating state that includes the display driver sending a synchronization signal, and monitoring for the synchronization signal during a first time period after sending the first command signal. The method further includes sending a second command signal to the display driver to operate according to a second operating state that includes the display driver withholding sending the synchronization signal, and monitoring for the synchronization signal during a second time period after sending the second command signal. In addition, the method includes detecting a display driver error based on results of the monitoring during at least one of the first or the second time periods.

RELATED APPLICATIONS

This application is a non-provisional application of commonly assignedU.S. Provisional Patent Application No. 61/827,724, filed on May 27,2013, from which benefits under 35 USC §119(e) are hereby claimed andthe contents of which are hereby incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to error detection features forsystems that display image data and more particularly to a method andsystem for detecting display driver error.

BACKGROUND

Systems that present photo or video data to a user include electroniccomponents, such as a display driver integrated circuit (IC) alsoreferred to herein simply as a display driver or a driver, which aresusceptible to errors. Some errors result from internal software processor hardware malfunctions. Other errors result from external influencessuch as electrostatic discharge, which can damage the electroniccomponent.

A conventional solution to detect display driver errors requires abi-directional communication interface between a control processor andthe display driver, where the control processor requests the contentinformation of a register in a memory of the display driver. When thecontents are different than expected, the control processor detects adisplay driver error.

One problem is that systems that do not have this bi-directionalcommunication interface between a control processor and display drivercannot use the above conventional display driver error detectionprocedure. Moreover, the above conventional error detection proceduresuffers from statistical uncertainty. More particularly, the proceduredoes not check the contents of each register within the display driver.Therefore, although a specific register may come back with valid contentinformation, this is not a guarantee that other registers within thedisplay are not corrupted.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, together with the detailed description below, are incorporated inand form part of the specification, and serve to further illustrateembodiments of concepts that include the claimed embodiments, andexplain various principles and advantages of those embodiments.

FIG. 1 illustrates a system diagram including apparatus for detectingdisplay driver error in accordance with an embodiment of the presentdisclosure.

FIG. 2 is a flowchart illustrating a method of detecting display drivererror in accordance with an embodiment of the present disclosure.

FIG. 3 is a flowchart illustrating a method of detecting display drivererror in accordance with an embodiment of the present disclosure.

FIG. 4 is a flowchart illustrating a method of detecting display drivererror in accordance with an embodiment of the present disclosure.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the disclosure herein.

The apparatus and method components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe disclosure herein so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

DETAILED DESCRIPTION

Generally speaking, pursuant to the various embodiments, a systempresents video data using a display driver, which is susceptible toerrors. Embodiments described herein detect when a display driver errorexists by monitoring for a correct synchronization signal response withrespect the display driver being commanded to operate in a particularstate or mode, such as an on (“ON”) state or an off (“OFF”) state. Inaccordance with some embodiments, a user is provided with a moreseamless use of the system or a decreased perceptible down timeresulting from display driver error by use of the method and system ofdetecting display driver error as described herein.

In one example embodiment, a method for detecting display driver errorincludes: sending a first command signal to a display driver to operateaccording to a first operating state that includes the display driversending a synchronization signal; and monitoring for the synchronizationsignal during a first time period after sending the first commandsignal. The method further includes detecting a display driver errorupon failing to receive the synchronization signal during the first timeperiod.

In another embodiment, a system provides for detecting display drivererror. The system includes a display driver configured to send asynchronization signal after receiving a first command signal to operateaccording to a first operating state. The system further includes aprocessor that is coupled to the display driver over an interface. Theprocessor is configured to: send the first command signal; initiate atimer for a first time period; and monitor for the synchronizationsignal during the first time period. The processor is further configuredto detect a display driver error upon failing to receive thesynchronization signal during the first time period.

In another example embodiment, a method for detecting display drivererror includes sending a first command signal to a display driver tooperate according to a first operating state, which includes the displaydriver sending a synchronization signal, and monitoring for thesynchronization signal during a first time period after sending thefirst command signal. The method further includes sending a secondcommand signal to the display driver to operate according to a secondoperating state, which includes the display driver withholding sendingthe synchronization signal, and monitoring for the synchronizationsignal during a second time period after sending the second commandsignal. The method further includes detecting a display driver errorbased on results of the monitoring during at least one of the first orthe second time periods.

Referring now to the drawings, FIG. 1 illustrates an embodiment of asystem 100 for detecting display driver error, in accordance with thepresent disclosure. FIG. 1 illustrates example hardware, which mayoperate using one or more software modules or routines, which performembodiments of the methods described herein. In the embodimentillustrated in FIG. 1, the system 100 is an electronic device that has ahousing 112 that includes a number of electronic components, at leastsome of which operate to perform embodiments of methods describedherein. Thus the terms electronic device and system are in someinstances used interchangeably herein. The electronic components showninclude: a processor 104, which in this case is an applicationprocessor; a display driver IC 102 having a random access memory (RAM)118; and a display 110.

In alternative embodiments, some of the components shown, such as thedriver 102 and the processor 104, are housed separately from the housing112 that houses the display 110. For example, in an embodiment, amonitor houses the display 110, and the monitor is coupled to a computerthat houses both the driver 102 and the processor 104. In a differentembodiment, the driver 102 and the processor 104 are also housedseparately from each other. Moreover, other electronic components of theelectronic device 100 are not shown in an effort to focus on thedisclosed embodiments and to keep the detailed description to apractical length. Such other components include, but are not limited to,additional processors and memory components, transceivers, additionalInput/Output (I/O) devices such as a keyboard, speakers, andmicrophones, etc.

Furthermore, although the driver 102 and application processor 104 areshown as separate components, in an alternative arrangement, thesecomponents are included within a single package such as on a single ICchip. Accordingly, system 100 may be implemented as any number ofdifferent types of electronic devices. These electronic devices include,by way of example, a computer and a monitor, a digital television, alaptop, a smartphone, a personal data assistant (PDA), a digital mediaplayer, a portable or mobile phone, a cellular phone, a personalwearable device, a tablet, a personal gaming system, a gaming systemconsole, a handheld gaming system, a notebook computer such as a netbookor an eReader, etc.

The application processor 104 supports video and other image-relatedand/or multimedia applications executable on the system 100, whichcommunicates image data to and from other devices or servers, forexample. The application processor 104 also connects to hardware such ascameras that are configured for capturing image data, which can bestored locally in the system 100 and/or communicated outside of thesystem 100. More particularly, the application processor 104 controlsthe display of image data on the display 110, by sending command signals(e.g., DRIVER AWAKE, DISPLAY ON, DISPLAY OFF, etc.) and image data tothe display driver 102. As used herein, image data, also referred toherein as data, is derived from a picture, for instance in the form ofvideo frames or still image frames also called picture frames.

The application processor 104 is configured to be coupled to the displaydriver 102 over a physical interface represented by 106 forcommunicating the command signals and image data. For example, theinterface 106 is a physical layer link implemented as one or more pinsbetween two ICs. In a particular embodiment, the physical interface isused to implement one or more logical channels. Examples of such logicalchannels include, but are not limited to, at least one data channel forcommunicating data such as image data, a control channel forcommunicating control data such as commands, and a clock channel forcommunicating timing information. The interface 106 can be aunidirectional interface from the application processor 104 to thedriver 102, as indicated by a link 116. In an alternative embodiment,the interface is a bidirectional interface between the applicationprocessor 104 and the driver 102, as indicated by links 116 and 124.

In an embodiment, the interface 106 supports one or more protocols forcommunicating the image data and control signals. In one particularembodiment, the interface 106 is a unidirectional Mobile IndustryProcessor Interface (MIPI). In another embodiment, the interface 106 isa unidirectional Mobile Industry Processor Interface. MIPIs supportnumerous protocols including, but not limited to M-PHY, D-PHY, DisplaySerial Interface (DSI), MIPI Unified Protocol (UniPro), Low LatencyInterface (LLI), SuperSpeed Inter-chip (SSIC), to name a few. As usedherein a MIPI is a chip-to-chip interface that conforms to standardscreated by the MIPI Alliance Standards Body, which standardizesinterfaces for mobile applications.

Referring back to FIG. 1, the display driver 102 is configured tooperate in accordance with the commands that the application processor104 provides over the link 116. The display driver 102 stores the imagedata received over the link 116 in the RAM 118 until it presents a formof the image data to the display 110 to enable the viewing of an imageor images represented by the image data. More particularly, while in anoperating state wherein the display driver is active (and the display isactive), for example, in response to a DISPLAY ON command, the displaydriver 102 converts the image data into a suitable signal that itprovides to the display 110 over a physical interface 114, which can bea link 120 as a unidirectional interface for instance. Alternatively,interface 114 is a bidirectional interface, as represented by links 120and 122.

In an embodiment, the interface 114 is a wire connection, such as a pin,over which the display driver 102 sends electrical signals at varyingvoltage levels, which represent the image data stored in the RAM 118.For example, the RAM 118 holds the image data for a single image orpicture frame. The display driver 102 loads its RAM content to thedisplay 110 by sending the frame to the display 110 row-by-row orline-by-line (in pixels) until the entire image is sent. In a particularembodiment, the display 110 is an optical display such as a liquidcrystal display (LCD) that translates the electrical signals that itreceives over the link 120 to optical signals by which the image can beseen through optical effects. For example, each pixel corresponds to acapacitor that is charged and slowly discharged to display the image. Inanother embodiment, the display 110 is an organic light emitting diode(OLED) display.

When the display driver 102 sends the last pixel of the frame, it waitsan amount of time before “refreshing” the display 110 by either sendingnew image data to the display 110, if the application processor 104 hasprovided the new image data, or rewriting the current image data to thedisplay 110. This amount of time that the display driver 102 waits iscalled a “scan retrace period” or “non-display period,” which isbasically a blanking interval between frames. The scan retrace ornon-display period can include at least some portion of a vertical backporch or front porch of the display area. The back porch appears as ablack or blank area on the bottom of the display 110 after a final pixelof a current frame is written; and the front porch appears as a black orblank area on the top of the display 110 before a first pixel of a frameis written.

During the scan retrace period, the display driver 102 sends asynchronization signal to the application processor 104 over a link 108,which can be an output pin. During the active state (also referred toherein as the “first” operating state) the display driver 102 sends thecurrent data (also referred to as “first” data) for a picture frame, forinstance the entire current contents of RAM 118, to display 110. In thiscase, the synchronization signal is synchronized to the display driver102 completing the sending of the first data to the display. Thesynchronization signal is, thereby, used to synchronize receipt by thedisplay driver 102 of the next image data (also referred to as “second”data) from the application processor 102, so that the display driver 102can send the next image to the display 110.

In an embodiment, the synchronization signal is a “tearing effect” (TE)signal that is a signal sent over a TE pin, e.g., 108, to prevent screentearing while displaying a frame on the display 110. Screen tearing is avisual artifact in video display where a display device or componentshows information from two or more frames in a single screen draw. Theartifact occurs, for instance, when the video feed to the display is notin sync with the display's refresh. During video motion, screen tearingcreates a torn look as edges of objects. The TE signal synchronizes whenthe display can be updated without getting any tearing effects. Thissignal basically indicates the scan retrace period of the display, whichcan be used to update the RAM 118; and the update is shown in the nextscan period. In a particular embodiment, during the non-display period,the TE goes high, which enables the application processor 102 to writenew image data to the display driver RAM 118 by observing the TE pin toavoid tearing.

For time to time during operation, the display driver 102 may enter intoa “lock-up state”, where the display driver is no longer operatingproperly. For example, the display driver 102 is no longer writing tothe display 110, even though the application processor 104 has commandedthe display driver 102 to the active state. Alternatively, theapplication processor has commanded the display 110 to a sleep state,but the display driver 102 continues to refresh the display 110. Thisdisplay driver lock-up state is also referred to herein as displaydriver error. In accordance with embodiments of the present teachings,for example as illustrated by reference to the remaining FIGS. 2, 3, and4, a system such as the system 100 and more particularly a controlprocessor such as the application processor 104 is configured fordetecting display driver error according to methods 200, 300, and 400,respectively. “Adapted,” “operative,” “capable” or “configured,” as usedherein, means that the indicated elements or components are implementedusing one or more hardware devices such as one or more operativelycoupled processing cores, memory devices, and interfaces, which may ormay not be programmed with software and/or firmware as the means for theindicated elements to implement their desired functionality. Suchfunctionality is supported by the hardware shown in FIG. 1.

In the method 200 and 300 embodiments illustrated by reference to FIGS.2 and 3, respectively, the application processor 104 is configured todetect display driver error upon commanding the display driver 102 tooperate according to a first operating state, which controls the displaydriver 102 to send a synchronization signal to the application processor104. With reference to FIG. 2, the first operating state includes thedisplay driver 102 awakening from a sleep state and sending thesynchronization signal, for instance in response to a command signalfrom the application processor 104. In a particular embodiment withrespect to FIG. 2, the first operating state includes the display driver102 awakening from a sleep state while the display 110 is in an offstate, and sending the synchronization signal to synchronize receipt offirst data for a first picture frame. With respect to FIG. 3, the firstoperating state includes the display driver 102 operating in an activestate, and sending the synchronization signal to synchronize theapplication processor 104 writing new image data to the RAM 118. In themethod 400 embodiment illustrated by reference to FIG. 4, theapplication processor 104 is configured to detect display driver errorupon commanding the display driver 102 to operate according to a secondoperating state, which controls the display driver 102 to withholdsending the synchronization signal.

Referring now to the method 200 embodiment illustrated in FIG. 2, theapplication processor 104 sends 202 an AWAKE command signal to thedisplay driver 102 over the link 116. The AWAKE command signal is sentto awaken the display driver 102 from a sleep state, while leaving thedisplay 110 in a sleep state. Such a command is useful, for example, toprepare the display driver 102 hardware for operation in anticipation ofusing the display 110 to present images. This helps to reduce thelatency of the device 100 as experienced by a user, which leads to abetter user experience. In another embodiment, the application processor104 at periodic intervals sends 202 the AWAKE command signal solely todetect whether the display driver 102 continues to operate properly.

With further respect to the FIG. 2 implementation, the display driver102 is configured to send at least one synchronization signal inresponse to receiving the AWAKE command signal. Correspondingly, theapplication processor 104 expects to see the at least onesynchronization signal from the display driver after sending the AWAKEcommand signal. Thus, the application processor 104 sets 204 a timer fora first time period. For example, the first time period is at least oneframe refresh duration. During 206 the first time period, theapplication processor 104 monitors 208 for the synchronization signal.If the application processor 104 receives the synchronization signalbefore the timer expires, the device including the application processor104 continues 212 normal operations, as there is no indication ofdisplay driver error. Normal operations may include the applicationprocessor 104 sending a signal to command the display driver 102 backinto the sleep mode, or sending a signal to command the display driver102 into the active mode.

Otherwise, if the timer expires 206 without the application processor104 receiving the synchronization signal, the application processor 104detects 210 a display driver error. For instance, display driver erroroccurs due to electrostatic discharge coming in contact with the system100 such as by virtue of a user touching an electrostatic source or sinkoutside of the system 100 or touching an object at a differentelectrostatic potential than the system 100. Electrostatic discharge toan electronic device can occur while the user is holding or otherwisetouching the housing of the electronic device or when the user istouching the display 110, such as where the display 110 incorporates atouch screen that is operated by tactile or touch input.

Referring back to the embodiment of FIG. 2, when display driver error isdetected 210, the processor 104 performs 214 an error recovery routine.An example error recovery routine is one that brings the driver 102 backto normal operation. For instance, the error recovery routine includesat least reinitializing 216 the display driver 102. In a furtherembodiment, for instance where the error occurred while the user wasmanipulating a graphical user interface (UI) on the display 110, theerror recover routine further includes recovering 218 the latest or lastUI.

Turning now to FIG. 3, the application processor 104 sends 302 a DISPLAYON command signal to the display driver 102 over the link 116. As withthe embodiment illustrated by reference to FIG. 2, the display driver102 is configured to send at least one synchronization signal inresponse to receiving the DISPLAY ON command signal. Correspondingly,the application processor 104 expects to see at least onesynchronization signal from the display driver after sending the DISPLAYON command signal. The application processor 104 then sends 304 imagedata, such as a picture frame or other type of data frame, to thedisplay driver 102 and sets 306 a timer for a first time period. In oneparticular interface embodiment, the image data is sent over aunidirectional Mobile Industry Processor Interface. In anotherembodiment, the data is sent over a bidirectional Mobile IndustryProcessor Interface.

During 308 the first time period, the application processor 104 monitors310 for one or more synchronization signal. If the application processor104 receives the expected number of synchronization signals before thetimer expires, the device including the application processor 104continues 312 normal operations, as there is no indication of displaydriver error. Normal operations, in this case, include the applicationprocessor 104 uploading 304 the next image data to the RAM 118. If thereare no more frames to upload, normal operations may include applicationprocessor 104 commanding the display driver 102 and the display 110 intoa sleep state.

In one example implementation, the application processor 104 isconfigured to monitor 310 for receipt of the synchronization signalmultiple times during 308 the first time period. For instance, uponawakening from the sleep state to the active state, the applicationprocessor 104 sets the timer before sending the first data. In thiscase, the first time period may cover a refresh period as well as anamount of time needed for the display driver to awaken and to send acorresponding command signal to awaken the display 110. The applicationprocessor 104 then monitors for a first synchronization signal duringthe first time period that indicates that the display driver 102 isready to receive image data. The application processor 104 continues tomonitor for a second synchronization signal that is synchronized withthe display driver 102 completing the sending of the data to the display110 and which alerts the application processor 104 to upload new imagedata.

Alternatively, the application processor 104 expects and monitors 310for a single synchronization signal during the first time period, whichalerts the application processor 104 to upload the new image data. Infurther embodiments with respect to FIG. 2 and/or FIG. 3, the displaydriver 104 is configured to send any predetermined number ofsynchronization signals during the first time period. In this case, theelectronic device continues 312 normal operations only if all of thepredetermined number of synchronization signals is received 310 during308 the first time period. If the timer expires 308 with one or moreexpected synchronization signals failing to be received, the applicationprocessor detects 314 display driver error and executes 316 an errorrecovery routine, which at least includes getting the display driver 102back to normal operation, for instance through a rebooting function.

Referring now to the embodiment illustrated in FIG. 4, the applicationprocessor 104 sends 402 a DISPLAY OFF command signal to the displaydriver 102 over the link 116. The DISPLAY OFF command signal is sent tocause the display 110 and the display driver 102 to return to a sleepstate. Such a command is useful, for example, to conserve battery lifein the electronic device 100. Accordingly, the display driver 102 isconfigured to withhold sending a synchronization signal in response toreceiving the DISPLAY OFF command signal. Correspondingly, theapplication processor 104 does not expect a synchronization signal fromthe display driver after sending the DISPLAY OFF command, since thedisplay 110 should be off, and the display driver 102 should no longercontinue to send image data to the display.

Thus, to detect an error, the application processor 104 sets 404 a timerfor a second time period and monitors 408 for receipt of asynchronization signal during 406 the second time period. The secondtime period could have a time value that is equivalent to the first timeperiod but need not necessarily have the same time value. In thisembodiment, the application processor 104 detects display driver errorif a synchronization signal is detected 408 during the second timeperiod, since the display driver 102 should have ceased sendingsynchronization signals. Upon detecting the display error, theapplication processor 104 performs 410 an error recovery routine, suchas rebooting the display driver 102. However, if the applicationprocessor 104 fails to detect 408 a synchronization signal before thetimer expires, the device that includes the application processor 104continues 412 normal operations. Normal operations might include, atsome later time, commanding the display driver 102 to an awake state asdescribed by reference to FIG. 2 or to an ON state as described bereference to FIG. 3.

Embodiments illustrated in FIGS. 2, 3, and 4 may also be combined in asingle method that is executed by the application processor 104 todetect display driver error. For example, the method includes theapplication processor 104 sending a first command signal to a displaydriver 102 to operate according to a first operating state that includesthe display driver 102 sending a synchronization signal and monitors forthe synchronization signal during a first time period after sending thefirst command signal. The method further includes the applicationprocessor sending a second command signal to the display driver 102 tooperate according to a second operating state that includes the displaydriver 102 withholding sending the synchronization signal and monitoringfor the synchronization signal during a second time period after sendingthe second command signal. The application processor 104 detects adisplay driver error based on results of the monitoring during the firstor the second time periods or both. In the combined embodiment, thedisplay driver error is detected when the synchronization signal isreceived during the second time period, where no synchronization signalshould be received. The display driver error is also detected uponfailing to receive the synchronization signal during the first timeperiod, where at least one synchronization signal should be received.

In the foregoing specification, specific embodiments have beendescribed. However, one of ordinary skill in the art appreciates thatvarious modifications and changes can be made without departing from thescope of the invention as set forth in the claims below. Accordingly,the specification and figures are to be regarded in an illustrativerather than a restrictive sense, and all such modifications are intendedto be included within the scope of present teachings.

The benefits, advantages, solutions to problems, and any element(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeatures or elements of any or all the claims. The invention is definedsolely by the appended claims including any amendments made during thependency of this application and all equivalents of those claims asissued.

Moreover in this document, relational terms such as first and second,top and bottom, and the like may be used solely to distinguish oneentity or action from another entity or action without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions. The terms “comprises,” “comprising,” “has”,“having,” “includes”, “including,” “contains”, “containing” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises, has,includes, contains a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. An element proceeded by“comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . .a” does not, without more constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises, has, includes, contains the element. The terms“a” and “an” are defined as one or more unless explicitly statedotherwise herein. The terms “substantially”, “essentially”,“approximately”, “about” or any other version thereof, are defined asbeing close to as understood by one of ordinary skill in the art, and inone non-limiting embodiment the term is defined to be within 10%, inanother embodiment within 5%, in another embodiment within 1% and inanother embodiment within 0.5%. The term “coupled” as used herein isdefined as connected, although not necessarily directly and notnecessarily mechanically. A device or structure that is “configured” ina certain way is configured in at least that way, but may also beconfigured in ways that are not listed.

It will be appreciated that some embodiments may be comprised of one ormore generic or specialized processors (or “processing devices”) such asmicroprocessors, digital signal processors, customized processors andfield programmable gate arrays (FPGAs) and unique stored programinstructions (including both software and firmware) that control the oneor more processors to implement, in conjunction with certainnon-processor circuits, some, most, or all of the functions of themethod and/or apparatus described herein. Alternatively, some or allfunctions could be implemented by a state machine that has no storedprogram instructions, or in one or more application specific integratedcircuits (ASICs), in which each function or some combinations of certainof the functions are implemented as custom logic. Of course, acombination of the two approaches could be used. Both the state machineand ASIC are considered herein as a “processing device” for purposes ofthe foregoing discussion and claim language.

Moreover, an embodiment can be implemented as a computer-readablestorage medium having computer readable code stored thereon forprogramming a computer (e.g., including a processor) to perform a methodas described and claimed herein. Examples of such computer-readablestorage mediums include, but are not limited to, a hard disk, a CD-ROM,an optical storage device, a magnetic storage device, a ROM (Read OnlyMemory), a PROM (Programmable Read Only Memory), an EPROM (ErasableProgrammable Read Only Memory), an EEPROM (Electrically ErasableProgrammable Read Only Memory) and a Flash memory. Further, it isexpected that one of ordinary skill, notwithstanding possiblysignificant effort and many design choices motivated by, for example,available time, current technology, and economic considerations, whenguided by the concepts and principles disclosed herein will be readilycapable of generating such software instructions and programs and ICswith minimal experimentation.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

We claim:
 1. A method for detecting display driver error, the methodcomprising: sending a first command signal to a display driver tooperate according to a first operating state that comprises the displaydriver sending a synchronization signal; monitoring for thesynchronization signal during a first time period after sending thefirst command signal; and detecting the display driver error uponfailing to receive the synchronization signal during the first timeperiod.
 2. The method of claim 1 further comprising: sending a secondcommand signal to the display driver to operate according to a secondoperating state that comprises the display driver withholding sendingthe synchronization signal; monitoring for the synchronization signalduring a second time period after sending the second command signal;detecting the display driver error when the synchronization signal isreceived during the second time period.
 3. The method of claim 1,wherein the first operating state comprises the display driver awakeningfrom a sleep state and sending the synchronization signal.
 4. The methodof claim 1, wherein the first operating state comprises the displaydriver sending first data to a display, and sending the synchronizationsignal to synchronize receipt of second data to send to the display. 5.The method of claim 4, wherein monitoring for the synchronization signalduring the first time period comprises monitoring for receipt of thesynchronization signal multiple times during the first time period. 6.The method of claim 4, wherein the first data is sent over aunidirectional Mobile Industry Processor Interface.
 7. The method ofclaim 4, wherein the first data is sent over a bidirectional MobileIndustry Processor Interface.
 8. The method of claim 4, wherein thesynchronization signal comprises a signal sent to prevent screen tearingwhile displaying a frame on the display.
 9. A system for detectingdisplay driver error, the system comprising: a display driver configuredto send a synchronization signal after receiving a first command signalto operate according to a first operating state; a processor configuredto be coupled to the display driver over an interface, wherein theprocessor is configured to: send the first command signal; initiate atimer for a first time period; monitor for the synchronization signalduring the first time period; and detect the display driver error uponfailing to receive the synchronization signal during the first timeperiod.
 10. The system of claim 9: wherein the display driver is furtherconfigured to operate according to a second operating state afterreceiving a second command signal, wherein the second operating statecomprises the display driver withholding sending the synchronizationsignal; wherein the processor is further configured to: send the secondcommand signal; initiate a second timer for a second time period;monitor for the synchronization signal during the second time period;detect the display driver error when the synchronization signal isreceived during the second time period.
 11. The system of claim 9,wherein the display driver is configured to awaken from a sleep stateand send the synchronization signal in response to the first commandsignal.
 12. The system of claim 9, wherein the display driver isconfigured, while in the first operating state, to send first data tothe display and send the synchronization signal to the processor tosynchronize sending second data to the display driver.
 13. The system ofclaim 12, wherein the processor is configured to monitor for receipt ofthe synchronization signal multiple times during the first time period.14. The system of claim 9, wherein the interface comprises aunidirectional Mobile Industry Processor Interface.
 15. The system ofclaim 9, wherein the interface comprises a bidirectional Mobile IndustryProcessor Interface.
 16. A method for detecting display driver error,the method comprising: sending a first command signal to a displaydriver to operate according to a first operating state that comprisesthe display driver sending a synchronization signal; monitoring for thesynchronization signal during a first time period after sending thefirst command signal; sending a second command signal to the displaydriver to operate according to a second operating state that comprisesthe display driver withholding sending the synchronization signal;monitoring for the synchronization signal during a second time periodafter sending the second command signal; and detecting the displaydriver error based on results of the monitoring during at least one ofthe first or the second time periods.
 17. The method of claim 16,wherein the display driver error is detected when the synchronizationsignal is received during the second time period.
 18. The method ofclaim 16, wherein the display driver error is detected upon failing toreceive the synchronization signal during the first time period.
 19. Themethod of claim 16, wherein the first operating state comprises thedisplay driver awakening from a sleep state while the display is in anoff state and sending the synchronization signal to synchronize receiptof first data for a first picture frame.
 20. The method of claim 16,wherein the first operating state comprises the display driver sendingfirst data for a first picture frame to the display and sending thesynchronization signal, which is synchronized to the display drivercompleting the sending of the first data to the display.